Fosamprenavir and Hydrocodone and chlorpheniramine interaction
Fosamprenavir and Hydrocodone and chlorpheniramine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Hydrocodone and chlorpheniramine (Hydrocodone Polistirex and Chlorpheniramine Polistirex extended-release) label · effective 2025-06-26
Cytochrome P450 3A4 Interaction The concomitant use of Hydrocodone Polistirex and Chlorpheniramine Polistirex with all cytochrome P450 3A4 inhibitors may result in an increase in hydrocodone plasma concentrations, which could increase or prolong adverse drug effects and may cause potentially fatal respiratory depression.
Avoid the use of Hydrocodone Polistirex and Chlorpheniramine Polistirex in patients taking a CYP3A4 inhibitor or inducer [ see Warnings and Precautions (5.7) , Drug Interactions (7.2 , 7.3) ].
Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of hydrocodone.
Avoid the use of Hydrocodone Polistirex and Chlorpheniramine Polistirex in patients taking CYP3A4 inhibitors or inducers.
Avoid the use of Hydrocodone Polistirex and Chlorpheniramine Polistirex in patients who are taking a CYP3A4 inhibitor or inducer.
From the Fosamprenavir (Fosamprenavir Calcium) label · effective 2026-06-30
…Hypericum perforatum ) Lipid modifying agents: Lomitapide, lovastatin, simvastatin Non-nucleoside reverse transcriptase inhibitor: Delavirdine PDE5 inhibitor: Sildenafil (Revatio) (for treatment of pulmonary arterial hypertension) Sedative/hypnotics: Midazolam, triazolam Hypersensitivity to fosamprenavir calcium or amprenavir (e.g., Stevens-Johnson syndrome).
Fosamprenavir calcium/ritonavir: ↔ Amprenavir ↔ Esomeprazole Sedative/hypnotics: Midazolam, triazolam ↑Midazolam ↑Triazolam Coadministration is contraindicated due to potential for serious and/or life-threatening reactions such as prolonged or increased sedation or respiratory depression [see Contraindications (4)].
Narcotic analgesic: Methadone Fentanyl ↓ Methadone ↑Fentanyl Data suggest that the interaction is not clinically relevant; however, patients should be monitored for opiate withdrawal symptoms.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.